Kunkel B N, Bent A F, Dahlbeck D, Innes R W, Staskawicz B J
Department of Plant Pathology, University of California, Berkeley 94720.
Plant Cell. 1993 Aug;5(8):865-75. doi: 10.1105/tpc.5.8.865.
A molecular genetic approach was used to identify and characterize plant genes that control bacterial disease resistance in Arabidopsis. A screen for mutants with altered resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) expressing the avirulence gene avrRpt2 resulted in the isolation of four susceptible rps (resistance to P. syringae) mutants. The rps mutants lost resistance specifically to bacterial strains expressing avrRpt2 as they retained resistance to Pst strains expressing the avirulence genes avrB or avrRpm1. Genetic analysis indicated that in each of the four rps mutants, susceptibility was due to a single mutation mapping to the same locus on chromosome 4. Identification of a resistance locus with specificity for a single bacterial avirulence gene suggests that this locus, designated RPS2, controls specific recognition of bacteria expressing the avirulence gene avrRpt2. Ecotype Wü-0, a naturally occurring line that is susceptible to Pst strains expressing avrRpt2, appears to lack a functional allele at RPS2, demonstrating that there is natural variation at the RPS2 locus among wild populations of Arabidopsis.
采用分子遗传学方法来鉴定和表征拟南芥中控制细菌性病害抗性的植物基因。对表达无毒基因avrRpt2的丁香假单胞菌番茄致病变种(Pst)抗性改变的突变体进行筛选,结果分离出4个感病的rps(对丁香假单胞菌的抗性)突变体。rps突变体对表达avrRpt2的细菌菌株特异性地丧失抗性,因为它们对表达无毒基因avrB或avrRpm1的Pst菌株仍保持抗性。遗传分析表明,在这4个rps突变体中,感病性均归因于位于第4号染色体上同一基因座的单个突变。鉴定出对单个细菌无毒基因具有特异性的抗性基因座,表明该基因座(命名为RPS2)控制对表达无毒基因avrRpt2的细菌的特异性识别。生态型Wü-0是一种对表达avrRpt2的Pst菌株敏感的天然品系,似乎在RPS2处缺乏功能性等位基因,这表明拟南芥野生种群中RPS2基因座存在自然变异。